1. Field of Invention
The present invention relates to a process for the fabrication of a composite of carbon fiber with metal.
2. Related Art
At present, for the purpose of reducing the weight or improving the mechanical properties, a so-called xe2x80x9cmetal-carbon fiber matrix composite materialxe2x80x9d obtained by complexing carbon fibers with a metal has been used in many industrial arts. This metal-carbon fiber matrix composite material has heretofore been prepared, e.g., by blowing metal particles onto a bundle of carbon fibers, vacuum-evaporating a metal onto a bundle of carbon fibers or infiltrating a bundle of carbon fibers with a molten metal.
However, the method involving the blowing of metal particles is disadvantageous in that the metal particles cannot penetrate deep into the bundle of carbon fibers, making it possible to provide a sufficient retention of metal and hence obtain a metalcarbon fiber matrix composite material having satisfactory mechanical properties. Further, the method involving the attachment of metal vapor or infiltration of a molten metal is disadvantageous in that since the carbon fibers exhibit a low wettability with a metal, the adhesion between the metal and the carbon fibers is poor, making it difficult for the metal to be introduced deep into the bundle of carbon fibers and retained therein. Moreover, a bundle of carbon fibers normally has fibers bundled with a sizing agent. This sizing agent renders the carbon fibers even less wettable with a metal. It has been occasionally practiced to remove the sizing agent from the bundle of carbon fibers before the contact with the metal. However, the bundle of carbon fibers which has thus been freed of sizing agent has its carbon fibers dissociated and thus can clog the orifice of an infiltration apparatus for infiltrating the bundle of carbon fibers with a molten metal, causing the suspension of production line.
As mentioned above, the foregoing various methods, i.e., method involving the blowing of metal particles, method involving the attachment of metal vapor or infiltration of a molten metal can hardly introduce a metal deep into the bundle of carbon fibers and retain the metal therein due to the low wettability of carbon fibers with a metal and the presence of a sizing agent in the bundle of carbon fibers.
The present invention has been worked out in the light of circumstances. An object of the invention is to provide a process for the preparation of a metal-carbon fiber matrix composite material having a great retention of metal which comprises enhancing the wettability of an inorganic fiber with a metal using a simple and easy method so that the metal can be introduced into the depths of the bundle of inorganic fibers.
In order to accomplish the foregoing object, the present invention provides a process for the preparation of a metal-carbon fiber matrix composite material which comprises removing a sizing agent from a bundle of carbon fibers, dipping the bundle of carbon fibers sequentially in an alkoxide solution and an alcohol, and then infiltrating the bundle of carbon fibers with a molten metal.
In the foregoing process, the infiltration of a molten metal is preferably carried out by continuously passing the bundle of carbon fibers which has been dipped in an alcohol through a molten metal charged in a bath container provided with orifices for introducing and discharging the bundle of carbon fibers received in a pressure container.